How to merge UserControl Ribbon with main form Ribbon when Document is docked to TabbedView and unmerge it when Document is floating

If I try to Drag document1 to make it float, application shuts down. But if I try to drag any other document than document1 first to make it float, then everything working fine.

Hello,
When you drag document1, the ActiveDocument property returns the null value and NullReferenceException is thrown. Add the null check in the DocumentActivated  event as follows:

C#
void tabbedView1_DocumentActivated(object sender, DevExpress.XtraBars.Docking2010.Views.DocumentEventArgs e) {  
    this.Ribbon.UnMergeRibbon();  
    int index = 0;  
    foreach (Document document in this.tabbedView1.Documents) {  
        if (!this.tabbedView1.Documents[index].IsFloating) {  
            if (document.Control != null) {  
                this.Ribbon.MergeRibbon((document.Control as UserControl1).Ribbon);  
            }  
        }  
        index++;  
    }  
    if (this.tabbedView1.ActiveDocument != null)  
        this.Ribbon.MergeRibbon((this.tabbedView1.ActiveDocument.Control as UserControl1).Ribbon);  
}  

Attached is the modified sample.

Thank you - everything is working fine.

You are always welcome.
Should you have further questions, let me know.

I have some questions - please, see attached project - as you cans see, only active document ribbon is merged with main ribbon while other ribbons is shown in their respective tabs.
Is there any way to hide(merge?) ribbon while document is docked as tab and shoe it when document is floating?

Hello,
To accomplish this, I suggest that you change RibbonControl's visibility. Attached is the modified sample that demonstrates my basic idea. Please review it and let me know if this is helpful.

Thank you - everything is working just fine!